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目的:评价下颌后牙区种植支持单冠(种植单冠)的面高度对种植体周围骨内应力分布的影响。方法:建立右下第二前磨牙种植单冠、近远中天然邻牙、牙周膜、牙槽骨、加载用刚体及模拟杏仁食物的三维有限元模型。采用国际牙科联合会系统(Federation Dentaire International system,FDI)命名法,以44、45、46分别代表右下第一前磨牙、右下第二前磨牙及右下第一磨牙。分别进行单牙最大力(44加载280 N,45加载360 N,46加载480 N)及平均力(44加载140 N,45加载180 N,46加载240 N)独立加载、联合加载(各牙位最大力之和转换为3.7 MPa,均布载荷加载于刚体上表面,刚体与各牙冠部接触点确定关系)及模拟杏仁的食物加载(各牙位平均力之和转换为1.67 MPa,均布载荷加载于模拟杏仁的食物上表面,食物与各牙冠部接触点确定关系),研究种植单冠3种不同面高度(正常高度、低15μm及低30μm)对于种植体周围骨内应力分布的影响。结果:在最大力独立加载时,46、45、44周围骨组织内Von Mises应力峰值分别为82.57 MPa、45.26 MPa、27.79 MPa;在平均力独立加载时,Von Mises应力峰值分别为41.28 MPa、22.63 MPa、13.89 MPa。在联合加载时,种植单冠低30μm与正常高度组相比,45应力峰值降幅为4.6 MPa,降低了0.84%;46应力峰值增幅为7.52 MPa,增加了20.04%;44应力峰值降幅为1.8 MPa,降低了5.84%。在模拟杏仁食物加载时,种植单冠低30μm与正常高度组相比,45应力峰值降幅为0.34MPa,降低了1.62%;46处应力峰值增幅为1.11 MPa,增加了2.66%;44处应力峰值增幅为0.06 MPa,增加了0.54%。结论:在本研究条件下,降低种植单冠面高度30μm范围内,种植体周围骨内应力峰值没有明显的变化。
OBJECTIVE: To evaluate the effect of anterior cruciate ligament (PCA) implant face height on the stress distribution in the peri-implant bone graft. Methods: A three-dimensional finite element model of single right crown, near and far natural adjacent teeth, periodontal ligament, alveolar bone, loaded rigid body and simulated almond food was established. Using the Federation Dentaire International system (FDI) nomenclature, 44,45,46 represent the lower right first premolar, the lower right second premolar and the lower right first molar, respectively. The maximum force of single tooth (280 N for 44 load, 360 N for 45 load, 480 N for 46 load) and the mean force (44 load for 140 N, 180 load for 180 load and 240 load for 46 N load) The maximal force of the tooth was converted to 3.7 MPa, the uniform load was loaded on the upper surface of the rigid body, and the contact point between the rigid body and each tooth crown was determined) and the food load of the simulated almond (the sum of the average force of each tooth was converted to 1.67 MPa, the uniform load was loaded on the upper surface of the almond food simulation, the relationship between food and the contact points of the crown was determined), and the effects of planting single crown on the height of the three different noodles (normal height, low 15μm and low 30μm) Body around the bone stress distribution. Results: The maximum Von Mises stresses in bone tissue around 46, 45, and 44 were 82.57 MPa, 45.26 MPa and 27.79 MPa, respectively. The average Von Mises stress peaks were 41.28 MPa , 22.63 MPa, 13.89 MPa. Compared with the normal height group, the peak stress of 45 stress peak decreased by 4.6 MPa and decreased by 0.84% when the single crown was lowered by 30 μm; the stress peak amplitude increased by 7.52 MPa, increased by 20.04%; and the peak stress decreased by 44% MPa, a decrease of 5.84%. Compared with the normal height group, the peak stress of 45 stress decreased by 1.34% and the stress peak amplitude increased by 1.11 MPa at 46, which increased by 2.66% and 44 stress The peak increase is 0.06 MPa, an increase of 0.54%. CONCLUSION: Under the conditions of this study, there was no significant change in the peak bone stress around the implants in the range of 30 μm when the crown height was reduced.